static void Zliczanie(char[] tab)
        {
            char[] litery = { 'A', 'B', 'C', 'D', 'E', 'F' };
            char[] nowa = new char[tab.Length];
            int[] ileWartosci = new int[6];
            for (int i = 0; i < tab.Length; i++)
            {
                switch(tab[i])
                {
                    case 'A':
                        ileWartosci[0]++;
                        break;
                    case 'B':
                        ileWartosci[1]++;
                        break;
                    case 'C':
                        ileWartosci[2]++;
                        break;
                    case 'D':
                        ileWartosci[3]++;
                        break;
                    case 'E':
                        ileWartosci[4]++;
                        break;
                    case 'F':
                        ileWartosci[5]++;
                        break;
                }
            }
            int j = 0;
            for (int i = 0; i < ileWartosci.Length; i++)
            {
                while(ileWartosci[i]>0)
                {
                    nowa[j] = litery[i];
                    j++;
                    ileWartosci[i]--;
                }
            }
            nowa.CopyTo(tab, 0);
        }